Mercury - Primer Bulb Fuel System Component Black Rubber 8M0052976. Overview. If you've spent any time around outboards, you know how good it feels when the engine fires up on the first try. That little moment of relief-when the motor catches cleanly and you can ease away from the dock-often comes down to simple, dependable parts doing their job. The Mercury 8M0052976 Primer Bulb is one of those quiet heroes. With every squeeze, it sends fuel forward with a steady pulse, giving your engine the p